Despite fertilization efforts,phosphorus(P)availability in soils remains a major constraint to global plant productivity.Soil incorporation of biochar could promote soil P availability but its effects remain uncertain...Despite fertilization efforts,phosphorus(P)availability in soils remains a major constraint to global plant productivity.Soil incorporation of biochar could promote soil P availability but its effects remain uncertain.To attain further improvements in soil P availability with biochar,we developed,characterized,and evaluated magnesium-oxide(MgO)and sepiolite(Mg4Si6O15(OH)2·6H2O)-functionalized biochars with optimized P retention/release capacity.Field-based application of these biochars for improving P availability and their mechanisms during three growth stages of maize was investigated.We further leveraged next-generation sequencing to unravel their impacts on the plant growth-stage shifts in soil functional genes regulating P availability.Results showed insignificant variation in P availability between single super phosphate fertilization(F)and its combination with raw biochar(BF).However,the occurrence of Mg-bound minerals on the optimized biochars’surface adjusted its surface charges and properties and improved the retention and slow release of inorganic P.Compared to BF,available P(AP)was 26.5%and 19.1%higher during the 12-leaf stage and blister stage,respectively,under MgO-optimized biochar+F treatment(MgOBF),and 15.5%higher under sepiolite-biochar+F(SBF)during maize physiological maturity.Cumulatively,AP was 15.6%and 13.2%higher in MgOBF and SBF relative to BF.Hence,plant biomass,grain yield,and P uptake were highest in MgOBF and SBF,respectively at harvest.Optimized-biochar amendment stimulated microbial 16SrRNA gene diversity and suppressed the expression of P starvation response and P uptake and transport-related genes while stimulating P solubilization and mineralization genes.Thus,the optimized biochars promoted P availability via the combined processes of slow-release of retained phosphates,while inducing the microbial solubilization and mineralization of inorganic and organic P,respectively.Our study advances strategies for reducing cropland P limitation and reveals the potential of optimized biochars for improving P availability on the field scale.展开更多
基金support was received from the Guangdong Basic and Applied Basic Research Foundation(2022B1515020014)China Postdoctoral Science Foundation(2023M743544)+1 种基金Fujian Forestry Science and Technology Promotion Project(2020TG17)the University-Industry Cooperation Project of Fujian Province(2021N5002).
文摘Despite fertilization efforts,phosphorus(P)availability in soils remains a major constraint to global plant productivity.Soil incorporation of biochar could promote soil P availability but its effects remain uncertain.To attain further improvements in soil P availability with biochar,we developed,characterized,and evaluated magnesium-oxide(MgO)and sepiolite(Mg4Si6O15(OH)2·6H2O)-functionalized biochars with optimized P retention/release capacity.Field-based application of these biochars for improving P availability and their mechanisms during three growth stages of maize was investigated.We further leveraged next-generation sequencing to unravel their impacts on the plant growth-stage shifts in soil functional genes regulating P availability.Results showed insignificant variation in P availability between single super phosphate fertilization(F)and its combination with raw biochar(BF).However,the occurrence of Mg-bound minerals on the optimized biochars’surface adjusted its surface charges and properties and improved the retention and slow release of inorganic P.Compared to BF,available P(AP)was 26.5%and 19.1%higher during the 12-leaf stage and blister stage,respectively,under MgO-optimized biochar+F treatment(MgOBF),and 15.5%higher under sepiolite-biochar+F(SBF)during maize physiological maturity.Cumulatively,AP was 15.6%and 13.2%higher in MgOBF and SBF relative to BF.Hence,plant biomass,grain yield,and P uptake were highest in MgOBF and SBF,respectively at harvest.Optimized-biochar amendment stimulated microbial 16SrRNA gene diversity and suppressed the expression of P starvation response and P uptake and transport-related genes while stimulating P solubilization and mineralization genes.Thus,the optimized biochars promoted P availability via the combined processes of slow-release of retained phosphates,while inducing the microbial solubilization and mineralization of inorganic and organic P,respectively.Our study advances strategies for reducing cropland P limitation and reveals the potential of optimized biochars for improving P availability on the field scale.
